This invention relates to an improved arrangement for detecting and sampling the decomposition products entrained in the coolant of a generator for the purpose of locating the source of the products.
Power generators occasionally fail due to localized overheating of their internal parts. The delay in locating the failure can result in great expense due to repair cost and long periods of down time. The overheating causes the organic coatings of the overheated parts to decompose giving off submicron products which are entrained in the coolant of the generator.
In U.S. Pat. No. 3,427,880, to Grobel et al., issued Feb. 18, 1969, there is described a system for the detection of overheating in a dynamoelectric machine. In that system the components for which overheating is to be detected are coated with a substance that produces submicron decomposition products at an ascertained temperature. A gas coolant which entrains the products is circulated through an ion chamber detector which detects the presence of the decomposed products. The Grobel et al. patent is concerned only with the detection of the presence of the products. However, since materials other than the coating substance may decompose, it is also desirable to be able to determine which substance decomposed and from where that substance came.
In U.S. Pat. No. 3,807,218, to Carson et al., issued Apr. 30, 1974, there is described a system for detecting and sampling products of thermal decomposition in a gas cooled dynamoelectric machine. In that system the coolant of the dynamoelectric machine is continuously monitored by an ion chamber detector. If the monitor detects these products, a valve system allows flow to a sampler which separates these products from the coolant. The sampler is removed and the sample is subjected to mass spectrometric or gas chromatographic analysis. From the analysis, it is possible to determine from which type of coating the product came. By knowing the coating of each part of the generator, the location of the overheating can be determined which greatly reduces the time necessary to repair the generator. It is also possible to coat the various generator parts with materials that decompose before there is serious damage to the parts thereby avoiding a failure of the part.
In copending application Ser. No. 426,391 filed Dec. 19, 1973 by Fort et al and assigned to the present assignee, there is described a system for automatically sampling a gas stream in response to a signal from the monitor that has been checked for its authenticity. The copending application also describes an improved sampling device.
Occasionally, either by accident or by necessity, multiple samples are taken on a sampler. Although the prior art describes a method for taking a sample, it does not solve the problem of taking multiple samples at different times and under different circumstances without obscuring the results of any individual sample.